The 707-horsepower Hellcat engine, a supercharged 6.2 liter Hemi V8, has rewarded Dodge with much higher sales than expected, along with a great deal of publicity in both magazines and social media.

The engine, carefully set up so that it can be run “all day” at the track on hot summer days — unlike at least one competitive Camaro — seems to be a real winner, but it’s available only in two cars, the closely related Challenger and Charger. In the Challenger, buyers can get a manual or automatic; in the Charger, it’s all automatic, but that automatic responds far more quickly than even a well-trained human can.

As Chrysler and its suppliers work to boost production of the Hellcat engine (particularly the unique supercharger), the next question becomes, “Which car is next?”

There are two real possibilities, both of which have been rumored: the Ram 1500 and the Jeep Grand Cherokee. The Jeep is the more credible choice, because the Grand Cherokee SRT has been a hit — and has been able to command a higher price than most FCA US cars. In addition, the suspension has already been tuned for performance with the 392 engine, which puts out 485 horsepower.

Jeep Grand Cherokee is a worldwide seller, and a Hellcat version would certainly be relatively popular in parts of the world where Rams are rare if available at all.

Ram, on the other hand, would be much harder to performance-tune; engineers would be starting from scratch, rather than building on work already done. Packaging might be easier, but would it sell more normal Rams, the way a Grand Cherokee Hellcat would sell more of the 6.4 SRTs?

All indicators, and our own long ears, are that the next Hellcat will be a Grand Cherokee. There’s no point in waiting for it to come out this year, though — demand for the hot engine means that it’ll be restricted to large cars for the moment, simply because orders exceed supply.

The all-new 2015 Dodge Challenger SRT, with its supercharged 6.2-liter HEMI Hellcat engine, produces an unprecedented 707 horsepower and 650 lb.-ft. of torque, making it the most powerful Challenger ever, Dodge’s most powerful V-8 ever and the most powerful muscle car ever.

The Challenger’s new 6.2-liter Supercharged Hellcat engine is also the first factory supercharged HEMI, as well as Dodge and SRT’s first application of V-8 supercharger technology. For the first time in Chrysler Group history, the all-new 2015 Dodge Challenger SRT with a Hellcat engine comes standard with two key fobs — red and black. The red key fob is the only key that can unlock the full 707 horsepower and torque potential of the Challenger SRT Hellcat engine; while the black key fob limits the driver to a reduced engine output of 500 horsepower.In addition to the awe-inspiring 707 horsepower of the new Hellcat HEMI, the new 2015 Dodge Challenger SRT Hellcat has been redesigned and totally re-engineered to be the most true-to-form muscle coupe on the market with performance-enhancing technologies inside and out, including the new TorqueFlite eight-speed automatic transmission and an all-new interior inspired by the classic 1971 Challenger.The Dodge and SRT brands now offer the most complete lineup of muscle cars in the market, including the new 2015 Dodge Challenger SXT with its standard powerful and fuel-efficient Pentastar V-6 engine combined with the TorqueFlite eight-speed transmission that delivers 300 horsepower and an estimated 30 miles per gallon; the 2015 Dodge Challenger R/T with the high-torque 5.7-liter HEMI now paired with the TorqueFlite eight-speed or six-speed manual transmission; and the all-new 6.4-liter HEMI Challenger Scat Pack that delivers 485 horsepower and 475 lb.-ft. of torque with the TorqueFlite eight-speed or six-speed manual.

The 2015 Dodge Challenger and Challenger SRTs are built at the Brampton, Ontario, Assembly Plant and will start arriving in Dodge dealerships in the third quarter of 2014.